Fort Dinwiddie was built in 1755, in the early months of the French and Indian War, by enclosing William Warwick's existing house with a log stockade. This was a common pattern on the Virginia frontier - settler homes that were defensible to begin with had walls thrown around them and were promoted to forts. Captain Andrew Lewis took initial command, but was relieved by Captain Peter Hog on September 21, 1755 - just three days before Washington's inspection visit. The fort sat on the Jackson River, five miles west of Warm Springs in what is now Bath County, Virginia. By 1756 it was garrisoned by 60 to 100 men. A log-covered passageway ran from one of the corner blockhouses down to a spring inside the fort, which meant the garrison could draw water without exposing themselves to attack.

Fort Dinwiddie was one stockade in a chain that Washington oversaw stretching across the Virginia frontier, 15 to 30 miles apart, intended to slow the raiding parties from the Ohio River valley. On July 21, 1756, Washington wrote to Captain Hog about extending the line further south: "As the Assembly has voted a chain of Forts to be built on the Frontiers, the Governor has ordered out the militia of Augusta to assist you in erecting them... to the Southward of Fort Dinwiddie, extending the Line towards Mayo River as directed by the Assembly." Hog was instructed to take most of his men south to build the new forts, leaving about 30 privates at Fort Dinwiddie under a Lieutenant Bullet. In October 1756, Washington visited Fort Dinwiddie again. He was building, supervising, inspecting - learning the trade of command that he would put to use a generation later.

The fort spent most of its existence as a muster point - a place where militia gathered before being deployed elsewhere. It saw only one significant engagement. In mid-June 1764, during Pontiac's War, a combined force of Delaware and Shawnee warriors attacked Fort Dinwiddie and laid siege to it for six hours. The fort held. The names of the warriors who fought there are mostly lost to history, but their attack was part of a broader Native American campaign to push back against British expansion after the French withdrawal - a fight for the Ohio and the upper Potomac watersheds, fought on the same ground where George Washington had ridden his inspection eight years earlier. Fort Dinwiddie was abandoned in 1789, six years after the Treaty of Paris ended the Revolutionary War.

Fort Dinwiddie was variously known as Warwick's Fort - after William Warwick, who owned the original house - Hogg's Fort, after Captain Peter Hog, and Byrd's Fort. Names rotated with commanders. For two centuries after its abandonment, the precise location of the fort drifted into uncertainty. In April 1971, a team of archaeologists from the Virginia State Library finally confirmed the site through excavation. The stockade walls were long gone, but the patterns in the soil, the postholes, and the artifacts told the story. The fort had stood where the records said it stood. The Jackson River still runs past the location today. The young colonel who inspected it has been gone for more than two centuries, but the records he kept - the letter to Captain Hog, the orders to Lieutenant Bullet - are still readable, still tell us exactly what was happening on this small stretch of Virginia frontier in 1755 and 1756.